Compounded lubricating oil



Patente rl'Apr. 30, 1940 PATENT OFFICE oomormnnnwaarcama on. i

Peter J. Wiezevich, Elizabeth, John' O. Zimmer, Hillside, and Arnold J. Morway, Roselle, N.J.; said Wiemevich, now by judicial change of name to Peter J. Gaylor, assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application November 6, 1930, Serial No. 109,546

10 Claims.

This invention relates to compounded lubricating oils which consist of mineral 'oil containing small percentages of metallic soaps, and is more particularly concerned with stabilizing agents,

therefor.

with metallic soaps, such as aluminum soaps of saturated fatty acids having more than ten carbon' atoms. These soaps serve to improve the properties of the lubricating oil, particularly for use in Diesel, automotive, and other combustion 'type engines. The soaps are usuallyadded in quantities varying from 1 to 5%.

It is found that thesoap does not remain completely dispersed in the lubricating oil but tends to separate out on standing orto cause gel formation. It is desirable in all cases where compounded lubricating oils are to be used in internal combustion engines to preserve the fluid characteristics of the lubricating oil and to prevent, in so far as possible, any gel formation;

It is an object of the present invention to provide certain substances which act as stabilizing agents to prevent the gelation of suchvmetallic soaps in lubricating oil. The nature of these stabilizing agents will be fully disclosed below.

It has been found that high boiling esters ofpolyhydroxy alcohols with monobasic acids, or of monohydroxy alcohols with polybasic acids, are especially satisfactory as stabilizing agents ing more than ten carbon atoms. The preferred esters are those having boiling points above 100 C. and preferably above 200 C. They may be added to lubricating oil containing from l'to 5% of aluminum soap in quantities from to .5 to 5 or even 10%.

The compounded lubricating oils according to the present invention are prepared by adding from 1 to 5% of aluminum soap, such as aluminum stearate, to a lubricating oil having a Saybolt viscosity at 210 F. varying between and 200 seconds. To this mixture is then added small percentages of the high boiling esters which'act in the capacity of a stabilizing agent. 0 As examples of the high boiling esters of polyhydroxy alcohols with monobasicacids may be mentioned glycol mono-propionyl (propionate), glycerylmonostearate glyceryl diacetate (diacetin), lycerol triacetate (triacetin). glycol monobutyrate, diglycol triacetate, and diglyceryl' naphthenate. Of these esters the glycol propionyl is especially suitable.

As examples of high boiling esters of mono- I hydroxy alcohols with polybaslc acids may be I Lubricating oils are frequently compounded mixture is heated while agitating to 300 F. and

for'aluminum soaps of saturated fatty acids havmentioned triethyl citrate, tricresyl phosphate, and oleyl malonate. Of these esters tricresyl phosphate is especially suitable.v

In many cases it is desirable also to add to the compounded lubricating on certain oxidation inhibitors which prevent corrosion of copper-lead bearings by the soap. As examples of suitable oxidation inhibitors for this purpose may be men tioned phenol sulfides or disulfldes', such as tertiary butyl phenol sulfide, secondary amyl phenol disulflde, amyl trisulflde, and a mixture of ben zldine with diethyl tartrate. In addition to these materials other substances may be added, such as thickening agents, dyes, pour inhibitors, oiliness agents, and in general any other type of sub- 15 stances which may be added to lubricating oil to improve its properties.

The following examples will illustrate the invention:-

Example 1 a 1% aluminum stearate-and .1% glycol monopropionyl are added to a Coastal Pale Oil having a Saybolt viscosity at 210 F. of 65 seconds. This allowed to cool. The mixture on cooling is a uniform, clear, transparent lubricating oil, free from gelled particles and especially suitable for Diesel engine lubrication.

Example 2 4% aluminum stearate and .4% glycol monopropionyl are added to a paraflin distillate hav-' ing a Saybolt viscosity at 210 F. of 40 seconds. The mixture is heated to 300 F. while stirring vigorously and then allowed to cool.

Example 3 1% aluminum stearate and 1% of tricresyl phosphate is added to a Coastal Pale Oil having a Saybolt viscosity of seconds at 210 F. The mixture is heatedto 300 F. while stirring vigorously and allowed to cool. This lubricant is a free-flowing oil suitable for internal combustion engine lubrication. The oil is particularly enhanced by the addition of the tricresyl phosphate forming a lubricant of high film strength.

This invention is not limited by any theories of the mechanism of "dispersion nor by any details which have been given merely for purposes oi illustration, but is limited only in and, by the following claims in which it is intended to claim ,all novelty inherent in the invention.

We claim: 1. An improved normally liquid lubricating oil comprising mineral oil, an aluminum soap, and I a small percentage 01. a high boiling selected from. the class consisting of esters of polyhydroxy alcohols with monobasic acids.

2. An improved normally liquid lubricating oil comprising a petroleum lubricating fraction, an aluminum soap of' a saturated fatty acld'having more than ten carbon atoms, and a small percentage of a high boiling ester oi a polyhydroxy alcohol with a monobasic acid.

3. An improved normally liquid lubricating oil comprising a petroleum lubricating fraction, 1

to 5% of stearate and between .001 and-5"% of an ester boiling above 200 0.. selected a from the class consisting of esters ofpolyhydroxy alcohols with monobasic acids. v 4. An improved normally liquid lubricating oil comprising a petroleum lubricating traction, 1

to 6% of aluminum stearate, and a small per- I comprising a lubricating traction of petroleum, 1 5% of aluminum stearate and between 0.001

and 5% of an ester boiling above-200 C. selected from the class consisting of esters of unsubstituted polyhydroxy alcohols with monobasic acids. I 7. An' improved normally liquid lubricating oil f comprising mineral oil, aluminum soap, and a small percentage of a high boiling hydroxy ester of a. monobasic acid.

' 8. An improved normally liquid lubricating oil comprising a lubricating fraction of petroleum, 1 to 5% of "aluminum stearate and between 0.001

and 5% of a hydroxy ester of a monobasic acid, said ester having a boiling point above 200 C.

9.:An improvedsnormally liquid lubricating 011 comprising a petroleum lubricating fraction, approximately '1% or aluminum stearate, and approximately 0.l% of glycol propionyl.

10. An improved normally liquid lubricating oil comprising a petroleum lubricating iraction,.1

to 5% or an aluminum soap of a saturate fatty 20 acid having more than 10 carbon atoms, and 0.001 to 10% of an ester of la polyhydroxy alcohol with a monobasic acidysaid ester having a boiling point above L100 C.

PETER J. WIEZEV-ICH. JOHN C.ZIM1VIER. ARNOLD J. MORWAY. 

